1. Field of the Invention
The present invention is related to a motor driving apparatus, and more particularly related to a driving apparatus to adjust motor rotation slope. There is a PWM modulation block to adjust the PWM pulse wave to vary the inputted PWM signal and the motor can have different rotation speed at the same PWM input signal so as to increase the flexibility of the implementation of the motor. In addition, the motor driving apparatus in the present invention is a signal phase motor or a three-phase motor.
2. Description of the Prior Art
The conventional motor driving method controlled by the pulse width modulation (PWM) is that the input duty of the PWM is corresponding to the output duty of the motor, as shown in FIG. 1A. For example, when the input duty cycle of the PWM is 50%, the output duty cycle of the motor is 50%. Therefore, the control curve of the duty of the motor is a linear curve, as shown in FIG. 1B.
The user would like to change the duty of the motor in accordance with the practical operation situation by adjusting the input duty cycle of the PWM. For example, when the temperature of the Central Processor Unit (CPU) of the personal desktop or laptop is increased, in order to decrease the temperature of the CPU, the input duty cycle is changed. Otherwise, the wire coil of the motor is changed to increase the duty of the motor when the duty cycle of the motor is the same. In a good design motor system, it is difficult to practically operate by implementing these two methods. For example, when the input duty cycle of the PWM by the controller (digital signal processor (DSP)) is changed in accordance with the practical operation situation, the control method in the whole system must be changed. When the wire coil of the motor must be changed, the motor has to be substituted.
In order to include the adjust function of the duty of the motor when the PWM controlling the motor to drive, there is a PWM modulation block is included in the PWM controlling motor driving apparatus to adjust the slop of the duty of the motor so as to include an adjust mode in PWM control. Therefore, the flexibility of the implementation of the duty of the motor is increased when the PWM control motor driving apparatus. The flexible of the PWM control motor driving apparatus to control the duty of the motor is creased.